Synthesis, Spectroscopic, Biological Activity, Molecular Docking and Density Functional Theoretical Investigations of Novel Tellurium(IV) Schiff Base Complexes

Aryltellurium(IV) complexes (3a-3f) of type RTeCl3.NMeIAP and R2TeCl2.NMeIAP (R belongs to 4-Hydroxyphenyl, 4-Methoxyphenyl and 3-Methy-4-hydroxyphenyl) have been synthesized from 3-((2-Hydroxyphenyl)imino)-1-methylindolin-2-one Schiff base ligand (NMeIAP or HL), prepared by the condensation of N-methylisatin and o-aminophenol in 1 : 1 molar ratio. The synthesized Schiff base and its aryltellurium(IV) complexes were characterized by molar conductance, FT-IR, elemental analyses, SEM analyses, powder X-ray diffraction, H-1 NMR, C-13 NMR, UV-Vis, mass spectrometry, DFT studies and thermogravimetric (TG) analysis. The stoichiometry of the compounds and the percentages of the different elements present in all compounds were confirmed by the elemental analysis. The Schiff base ligand behaved as a monobasic tridentate ONO chelating agent. The molecular structures of the ligand (NMeIAP) and its complexes were optimized theoretically and their electronic properties such as HOMO and LUMO energies were determined by def2-SVP calculations. Molecular docking studies was used to determine probable and effective binding modes between ligand and different active sites of the receptors. X-ray diffraction revealed the crystalline nature of the Schiff base whereas the complexes are semi crystalline in nature. NMeIAP and aryltellurium(IV) complexes were tested against bacteria: B. cereus and X. campestris. Antifungal activity was determined against C. albicans, F. oxysporum and S. sclerotium.